Conventional cutting inserts are typically formed by pressing a compactable material such as a tungsten carbide, or cermet, powder in a die to form a so-called “green body”, and sintering the green body to form a blank, the blank being subject to different finishing operations, such as grinding and coating, to form the final cutting insert product. FIGS. 1A-1B schematically show steps in the formation of a green body 321 with a simple shape in a press tool comprising a die 323, and top and bottom punch components 325 and 327, the die having a die wall 329. As schematically shown in FIG. 1C, the resulting green body 321 will have a relatively high density in the top and bottom region A and B adjacent the one or more movable punch components 325 and 327 of the press tool, a relatively low density in the middle region C, and an intermediate density in regions D and E between the top and bottom region and the middle region. The difference in density is mainly caused by the friction between the compactable material and the die wall 329 during the compaction by the upper and lower punch 325 and 327.
FIGS. 2A-2B schematically show steps in the formation of a green body 421 using a cross hole compaction process. In this process, the press tool has one or more movable punch components 425 and 427 and the die 423 has a die wall 429, and generally elliptical cross-hole pins 431 and 433 that are generally introduced into the die cavity before the material to be compacted is introduced, and the material is then compacted around the pins as the punch components move from the position shown in FIG. 2A to the position shown in FIG. 2B. The pins 431 and 433 are withdrawn and the resulting green body 421 is ejected from the die and will have a generally elliptical cross-hole 435 as schematically shown in FIG. 2C. The green body 421 will have a relatively high density in regions AA and BB above and below the cross hole 435, a relatively low density in regions CC to the left and right of the cross hole, and a medium density DD in the corner regions. The difference in density in a green body formed by the cross hole compaction process described with respect to FIGS. 2A-2C is mainly caused by the difference in compaction ratios due to the cross-hole pins. However, friction between the material being compacted and the die wall 429 during the compaction by the upper and lower punches 423 and 425 also contributes. The difference between the highest density and the lowest density in a green body with a circular or elliptical hole formed by the cross-hole compaction process described above is relatively high and can cause unwanted shape distortions during sintering of the green body, during which the green body shrinks. Due to shape distortions the sintered green body needs to be ground depending on final insert tolerances of the final product. FIG. 3 shows an illustrative green body 521 including a geometry formed in top and bottom sides 523 and 525 thereof that is the inverse of the shape of the one or more movable punch components (not shown) used to form the top and bottom surfaces. The green body 521 also includes a cross-hole 535 of the type that can be formed by elliptical pins as described in connection with FIGS. 2A-2B.